When used in an e-mail, apostrophes should not be encoded

Description

WordPress sends e-mail as plain text (as far as I know), and therefore special characters should not be encoded as HTML entities, but displayed as-is.

A French user has ​recently reported that WP does encode at least one character: the straight apostrophe ('). My guess is that it is to prevent any breakage further down the road, but in this case it makes the string hard to read.

Actual blog title: Le Mag'zine
Title as used in e-mail: Le Mag&#039;Zine